Motorcycle Rear Fender and License Plate Bracket Arrangement

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Solution Overview

Problem

Motorcycles with unit swing type engine units face challenges in achieving effective mudguard performance while maintaining a compact rear structure, as large license plate brackets are required for the mudguard function, leading to increased vehicle size and difficulty in compactly forming the rear part.

Innovation Solution

The design includes a license plate bracket positioned lower than the tail light unit and a rear fender extending from the engine body with a lower rear end than the license plate bracket, combined with slanted side covers and a storage box positioned higher than the side covers, allowing for a compact appearance and size while maintaining effective mudguard functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the license plate bracket is formed in a large size to enhance mudguard function, then the mudguard performance is improved, but the rear part of the motorcycle increases in size

Engineering Contradiction:
Improvemudguard performanceVSAvoidrear part size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent divides the mudguard function between two separate components: the license plate bracket (which provides partial mudguard protection) and the rear fender (which provides additional mudguard protection). This segmentation allows each component to be smaller than a single large mudguard structure while collectively achieving the same protective function, thus resolving the contradiction between mudguard performance and compact size

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The license plate bracket serves dual functions: supporting the license plate and providing mudguard protection. The rear fender similarly serves multiple functions including mudguard protection and aesthetic coverage. This multi-functionality reduces the need for dedicated separate components, enabling a more compact overall design while maintaining effective mudguard performance

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Stability of the object's composition

If the license plate bracket is disposed in a sufficiently rearward position to avoid contact with the rear fender, then the structural interference is eliminated, but the license plate bracket must be further vertically elongated to ensure mudguard function

Engineering Contradiction:
Improvestructural arrangementVSAvoidlicense plate bracket vertical length
Core Design Contradiction:
Stability of the object's compositionVSLength of stationary object

Solution Approach 1:

Instead of solving the spatial conflict between the license plate bracket and rear fender only in the horizontal dimension (by positioning the bracket rearward), the patent utilizes the vertical dimension by configuring the rear fender to extend downward. This dimensional approach allows the bracket to be positioned more forward while maintaining adequate clearance, reducing the need for vertical elongation

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The rear fender is configured to pivot with the rear wheel, creating dynamic clearance that adapts to the wheel's rotation and suspension movement. This dynamic configuration eliminates the need for excessive static clearance space, allowing more compact positioning of the license plate bracket while preventing contact during operation

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2221220B1Motorcycle
Publication Date: 2016.03.30 YAMAHA MOTOR CO LTD
  • EP2221220B1 patent drawingFigure 1
  • EP2221220B1 patent drawingFigure 2
  • EP2221220B1 patent drawingFigure 3

AI summary

A motorcycle of the present invention is provided with a unit swing type engine unit. Bottom edges of left and right side covers (32a, 32b) slant in a rearwardly upward direction. A storage box (35) is vertically disposed between a seat (3) and an engine unit (2), while being transversely disposed between the side covers (32a, 32b). Additionally, a bottom face of the storage box (35) is positioned higher than the side covers (32a, 32b) in a side view. A license plate bracket (44) is supported by a frame for being disposed lower than a tail light unit (40). A rear fender (48) rearwardly extends from a vicinity of an engine body (16). A rear end of the rear fender (48) is positioned lower than a bottom end of the license plate bracket (44). The rear fender (48) covers at least above of a rear wheel (6).